The present invention relates to workpiece supporting surfaces and, more particularly, to tiltable tables for use with woodworking tools.
Most multipurpose woodworking tools are of the type having a headstock which supports an electric motor having a horizontally-oriented output spindle, and a workpiece supporting table. Both the headstock and table are adjustably mounted on a pair of parallel, horizontally extending rails, so that the relative distance between the headstock and table can be varied, as well as their arrangement along the rails. The output spindle of the headstock is adapted to support a circular saw blade or other disk-shaped tool, and the table top includes a generally centrally located, transverse slot sized to receive at least a portion of the saw blade therethrough, so that the assembly may be operated as a table saw.
The headstock and circular saw blade typically are incapable of being pivoted in relation to the horizontally extending rails, so that in order to cut a beveled edge on a workpiece supported on the table, it is necessary to tilt the table so that the workpiece is disposed at an angle relative to the vertically oriented saw blade.
For example, the Edgemond, Jr. et al. U.S. Pat. No. 2,927,612 discloses a multipurpose woodworking tool having a headstock and tilting table mounted on a pair of parallel, horizontally extending rails, and the table top is pivotally mounted to a support member which includes a pair of vertically extending racks that are supported by a carriage mounted on the rails. The tilting mechanism comprises a trunnion, attached to the underside of the table and pivotally attached to the support member, and a pillow block which is also attached to the underside of the table and receives a pivot pin which extends outwardly from an opposite side of the support member. The trunnion includes an arcuate slot, and the support member includes a threaded bolt extending through the slot which receives a locking handle. Rotation of the locking handle on the bolt displaces the locking handle inwardly to clamp the trunnion against the support member to lock the table top and prevent tilting movement thereof. The support member also includes a spring-loaded detent pin which engages stops on the trunnion to facilitate the orientation of the table top at predetermined angles relative to the horizontal, such as 45.degree..
A disadvantage which such a tilting mechanism is that only a single locking member is employed, so that the side of the table top proximate the pillow block and away from the trunnion may tilt slightly during use as, for example, when the operator bears down to hold a workpiece against the table. Another disadvantage is that, to lock the table top, the locking lever must engage the trunnion, which may result in the marring of the trunnion body along the arcuate slot. To obviate this marring, it may be necessary to fabricate the trunnion from a wear-resistant, and hence expensive, material.
Other examples of tilting tables are shown in the Goldschmidt U.S. Pat. No. 2,747,626 and the Parker et al. U.S. Pat. No. 3,282,309. Each of these patents discloses a multipurpose woodworking tool having a tiltable table in which the table top is supported by a pair of trunnions, each having its own separate locking mechanism of the type described in the Edgemond, Jr. et al. patent. However, while this type of locking mechanism provides additional stability since both pivoting connections are locked relative to the support member, the operator must perform an additional operation to lock the table and to release the table to change its orientation. Hence, there is an opportunity for the operator of the woodworking tool to neglect to lock one of the trunnions, resulting in a table which may tilt during use and thus ruin the cut being made upon a workpiece.
Accordingly, there is a need for a tilting table adapted to be used on a multipurpose woodworking tool which provides a rigid locking mechanism that minimizes the possibililty of the table tilting during use. Furthermore, there is a need for a table tilting mechanism in which a single lever can be actuated to effect the locking of two pivotal connections between the table and support member.